1. Technical Field
The present invention relates to an ultrasonic device, a piezoelectric device, an ultrasonic measurement apparatus, and an electronic instrument.
2. Related Art
There is a known ultrasonic probe of related art including an ultrasonic transmitter that transmits and receives an ultrasonic wave, and the ultrasonic transmitter is electrically connected to a signal processing circuit section via a plate-shaped backing material layer, transmits an ultrasonic wave in accordance with a transmission pulse signal from the signal processing circuit section, and outputs a reception pulse signal to the signal processing circuit section in accordance with a received ultrasonic wave (see JP-A-2011-259274, for example).
The ultrasonic transmitter described in JP-A-2011-259274 includes a diaphragm and a support member that is disposed on the ultrasonic wave radiation side of the diaphragm and supports the diaphragm. The diaphragm, which is one of the components that form the ultrasonic transmitter, includes a thin-plate-shaped base material layer and a drive layer that serves as an electromechanical conversion element and is provided on the surface of the base material layer on the side opposite the support member (rear surface of base material layer). A through silicon via (TSV) substrate (sealing member) is provided on the rear surface side of the base material layer, and the TSV substrate covers the drive layer. Through electrodes provided in the TSV substrate are connected to the signal processing circuit section via the backing material layer in such a way that electricity can be conducted through the through electrodes. The diaphragm is thus fixed to the backing material layer and other components with the diaphragm supported by the sealing member, as described above.
In the ultrasonic probe (ultrasonic module) described in JP-A-2011-259274, however, the diaphragm provided with the drive layer is fixed to the signal processing circuit section, that is, a circuit substrate via the TSV substrate (sealing plate) and the backing material layer, resulting in a problem of an increase in the thickness dimension in the direction in which the diaphragm, the sealing plate, the backing material layer, and the circuit substrate are arranged and hence an increase in the size of the ultrasonic module.
To address the problem, it is conceivable to reduce the thickness dimension of the sealing member so as to suppress the increase in the size of the ultrasonic probe. In this case, however, since the rigidity of the sealing plate decreases, stress produced when the ultrasonic probe is brought into contact with a measurement target could undesirably deform or break the sealing plate and the diaphragm. The degree of the reduction in the thickness dimension of the sealing plate is therefore limited because the rigidity of the sealing plate needs to be ensured, and it is therefore difficult to reduce the size of the ultrasonic module with desired rigidity ensured.